Mainframe, alias Blaine L. Carter, is G.I. Joe's resident computer nerd. He's no pencil-necked geek, mind you - he joined the Army at seventeen, and after a brief, mind-numbing sojourn into Silicon Valley, he signed up with the Marines. Dude can probably kill you with a flash drive.

Devil's Due G.I. Joe vs. the Transformers comics continuity

While giving a presentation about a prototype satellite at Echelon 5, Mainframe was interrupted by Michael, who informed him of an image of one of the nascent Cobra organization's enslaved Transformers. Leaving the meeting, he left Michael in charge of completing the presentation. G.I. Joe vs. the Transformers #2 Now a member of G.I. Joe, Mainframe attempted to decode the message, but was unable to until the Joes' Autobot ally Wheeljack identified it as a coded message from Optimus Prime. The Autobot subsequently sent out a virus that freed all of Cobra's Transformers. G.I. Joe vs. the Transformers #3 Mainframe accompanied G.I. Joe on their mission to Cobra IslandG.I. Joe vs. the Transformers #4 and battled Cobra's forces there. G.I. Joe vs. the Transformers #5 With the reluctant aid of Dr. Mindbender, Mainframe and Wheeljack managed to use the SPS satellite Cobra had hijacked to shoot down the nuclear missiles the US government had launched at Cobra Island, preventing a global catastrophe - all while being shot at by Storm Shadow, Firefly, and a legion of Cobra soldiers. The satellite began firing randomly, endangering everyone on the island, until Mainframe and Sci-Fi transmitted its position to Optimus Prime, allowing him to shoot it down. G.I. Joe vs. the Transformers #6

Later, Mainframe attempted to defend the warpgate to Cybertron from Serpent O.R., but he was quickly struck down. The Art of War #2 After recovering, Mainframe and Doctor Li, a member of Serpent O.R.'s design team, attempted to repair the gate. When Mainframe sensed that Li was more interested in retrieving his creation than stopping its rampage, he punched the doctor's lights out. Working with Firewall and Li's colleague Martin, he managed to get it operational, and also learned the details of the Serpent O.R. project. Sending a small contingent of Joes and Autobots through the gate, Mainframe promised to send as much backup as he could find. The Art of War #3 True to his word, Mainframe sent an army of Joes to Cybertron to battle Serpent O.R. and his forces. The Art of War #4